diff --git a/src/core/js/ext_map.js b/src/core/js/ext_map.js
index 39e6d510f9bbdf8e18426dc9b56577a235850a8d..bac14e71f68561df6982f94fca9c5e9f02e8c90e 100644
--- a/src/core/js/ext_map.js
+++ b/src/core/js/ext_map.js
@@ -1585,7 +1585,7 @@ var caosdb_map = new function () {
                 var lat_vals = getProperty(map_entity, datamodel.lat);
                 var lng_vals = getProperty(map_entity, datamodel.lng);
 
-                if (!lng_vals || !lng_vals) {
+                if (!lng_vals || !lng_vals || lng_vals == "undefined" || lng_vals== "undefined") {
                     logger.debug("undefined latitude or longitude",
                         map_entity, lat_vals, lng_vals);
                     continue;